.layui-tab-title {
    background-color: white;
    box-shadow: 8px 1px 2px #cac3c3
}

.layui-this {
    background-color: #f6f6f6;
}

.layui-tab-title li {
    position: relative;
}

/*初始化伪元素的样式*/
.layui-tab-title li:after {
    content: '';
    width: 0px;
    height: 2px;
    background-color: black;
    position: absolute;
    top: 0;
    left: 0;
    border: none;
    transition: all 400ms;
}


/*鼠标悬浮到选项卡上*/
.layui-tab-title li:hover:after {
    content: '';
    width: 100%;
}

/*当前选中的伪元素*/
.layui-tab-title .layui-this:after {
    content: '';
    width: 100%;
    height: 2px;
    border: none;
}